Has anyone here binned the re-circ valves on there car.

 

I was thinking of do this and just blocking the hoses up, I have seen this done on 200sx without problems other that compressor stall noises.

 

What do you think?

mmmm not sure mate, i tired it for a little while, about an hour, and my idle went a bit pschizo.

 

Apexi twin chamber bovs mate, thats what i went for, fit in the same place as the recircs, if you take the time to set them up, they dont mess up your idle and are a quality bit of kit

 

my 2ps worth

 

nick

Has anyone here binned the re-circ valves on there car.

 

I was thinking of do this and just blocking the hoses up, I have seen this done on 200sx without problems other that compressor stall noises.

 

What do you think?

 

Yeah you can do that with no running issues, however the dump valves were fitted for a reason, releasing build up of pressure when the butterfly shuts, block em off and you lose the reason they were fitted in the 1st place. I must confess i've NEVER known anyone to purposely block them off without fitting new ones at the same time, but hey each to their own ;)

smithy

wouldnt blocking the recircs and not fitting atmospherics cause turbine stall? :nono:

Pretty much, that is the whole concept of dump valves, the stall is caused when you shut off the gas, butterfly shuts and built up pressure.

smithy

Alot of the drift boys are running without dump valves and I have been looking on sxoc and apparently s13 ca18 don't have them fitted as standard but I think this must be wrong. (I know very little about the s13).

 

I am more worried about damage to the turbos. on my s14a I used to get compressor stall all the time as my dump valve on opened at over a bar of pressure when backing off. (single piston so had to set it high to stop it leaking on idle). Never noticed any worsing of lag when I set the boost to ten psi during the winter.

 

The pidgeon sound is the compressor blades stalling.

The pidgeon sound is the compressor blades stalling.

Wait until you get the goose honk on the recirc! It's sooo funny driving pass someone while having the Z making a goose honk all the way pass them!

 

S13s dont have recirc at all and do not have any sort of dump valve as standard.

So therefore it can't be damaging to the car running without them then as why would Nissan not fit them if it was bad for the turbo / engine?

 

What the hell is goosehonk??????

So therefore it can't be damaging to the car running without them then as why would Nissan not fit them if it was bad for the turbo / engine?

 

What the hell is goosehonk??????

 

The common way of describing the noise the recircs make when they start to fail LOL

Do a search for goose honk or owls and you'll find hundreds of posts LOL

 

Probably not that bad for the turbo but maybe it's a noticeable change in performance on a Z?

Nissan wouldn't fit a couple of hundred quids worth of parts for no reason.

So therefore it can't be damaging to the car running without them then as why would Nissan not fit them if it was bad for the turbo / engine?

 

What the hell is goosehonk??????

 

I said that at the start, yer right engine wise it won't cause a problem.

Nissan didn't fit them to the s12 or s13 but did s14 and onwards to prevent the turbo slowing down on pressure build up and keep the boost curve smooth.

It's a complete senseless mod to remove them just for the sake of it as in doing so will not benefit you in anyway either, so why do it ? if it ain't broke, don't fix it.

But like i also said before, if yer wanna do it you'll be the only one ever heard off doing so for no apparant reason, so crack on.

cheers

smithy

re-circ ain't couple of hundred to make (maybe at Ni$$an prices), so why are they not fitted to a CA18, in fact I am sure the new scooby doesn't have it either.

 

I might remove them and run for a while to see if there is a performance difference as they can always be re-fitted, certainly the 200sx (s14s, & s15s) guys are saying there is no difference in performance and in fact alot of them are saying the idle is much better than with various different vent to atmosphere setups

I think you'll find the idle is very rough and the boost curve isn't as smooth but looks like you already decided to go a different way to all the thousands of UK, US, Aussie owners :D Good luck!

Don't know why you asked really :rofl:

I will try it and post results here.

 

I like to try things and see what happens, I know more about an SR20det than the VG30DETT but i am learning quickly and the only evidence I can find to tell me not to do this is it might eat the thrust bearing after 50K miles.

 

I have always used these forums as a starting point but have had a few conversations with professional tuners, and have often found things to be different for the expected results.

 

Example I read countless times on different forums that a vent to atmosphere would make my 200 run shit when backing off (jerky, stall), yet I never once had a problem with it and it ran smoothly at idle (once set-up correctly) on a single piston dump and not a twin piston which again everyone recomended, yet was totally unnecessary.

 

chris if the idle is very rough then there is other issues surely with the engine as there is no boost pressure so the recircs are doing nothing then anyway, if you are meaning when backing of then this is probably cause by the MAF reading the back surge of air and over fueling, will look out for this during the trial.

 

Also I have never seen a re-circ or dump valve on any pro rally car or any of the old turbo'd f1 cars, Phil Morrison has ran his turbo for over 6000 drift miles with no damage and he ain't got a dv or re-circ, I know it is a differnet car but, how many people here have actually done this and fully tested it over a few thousand miles.

rrrr this no edit function. let me clarifly this line

 

I have always used these forums as a starting point but have had a few conversations with professional tuners, and have often found things to be different for the expected results.

 

this should read

 

I have always used these forums as a starting point but have had a few conversations with professional tuners, and follow their advice have often found things to be different for the forum based expected results.

 

hope this makes more sence.

the way i see it is that you want to do this mod for the pigeon noise...

 

to get this noise you are sacrificing throttle response time when on and off boost and ul be changing the tubs every 6 months... thats if you change them before one fires all of its blades into the engine!

 

imo its not worth but as said previously, each to their own. :D

the idea of stalling a turbine then to ask it spool up again makes no sense when its only producing its "keep" by high rpm :confused:

LOL they did't fit intercoolers on some cars either so are you gonna remove those too? :tongue:

LOL they did't fit intercoolers on some cars either so are you gonna remove those too? :tongue:

 

Good thinking batman!

Why bother with turbos at all? The N/A never had them and they run really smooth!

Okay let me answer the throttle response, my 200sx had better response when the dump valve was removed! I have also had other people confirming this to me.

 

Joely P see my post above about it will only munch the thrust bearing after a very long time and the fact that if it was as damaging to turbos as you are suggesting all turbo'd cars would have them.

 

the noise by the way is cavitaion, i.e the blades choping the air rather than blowing it, as I said before certain professionally built cars do not run them with no side effects, yes modern rally cars have anti-lag systems, but early turbo'd motors didn't have anti-lag and suffered no increase in lag. Think about the money F1 and rally teams spend in research even in the early 80s if the was a major benefit for fitting one they would of.

 

The biggest benefit for fitting re-circs is for emisson reasons as both vent to atmosphere and complete removal cause overfueling on lift off.

 

I have been told by a couple of decent tuners dump valves shouldn't operater below certain boost pressure (depending on set up) so this means you are effectly running no DV on pressures below this. for example 15psi of boost is you max boost, DV set to 10psi, therefore everything upto 10psi will not open the DV when lifting off, therefore you will be running the pigeon mod. This is common since the springs holding the piston closed have to be of a certain stiffness in order to hold the piston shut at high boost levels to stop leakage.

 

I would only run this upto about 1 bar myself but other have run much higher.

think youll find its just an sr20 thing mate, the zed engine is very differently setup, probably wouldnt recommend it

I try it and see as it is easy to refit them if it fecks the car up.

This same disscussion came up on Scoobynet earlier in the week. Removing recirc/dv will give you compressor stall which gives you that twittering sound like the rally cars have. Rally cars do not run recirc/Dv but most road cars do (those that don't have other means of dealing with surplus pressure)... This is because rally car engines are not designed with an inteded 100k+ mile lifespan, road cars are. You will eventually knacker your turbos by running this way. How much sooner, who knows.

You do run a serious risk of twisting the turbo shafts as well...

my dump valve on opened at over a bar of pressure when backing off. (single piston so had to set it high to stop it leaking on idle). .

 

yet I never once had a problem with it and it ran smoothly at idle (once set-up correctly) on a single piston dump and not a twin piston which again everyone recomended, yet was totally unnecessary

 

The whole point of a twin piston is so u dont have to do the above. bit pointless really

sounds great but with air rushing back through the blades causes some stall and slight lag, TBH not really that noticable, and also in time it will damage shafts with time

 

but it does sound better than any recirc or DV ;)

I do love the sound of it but I wouldn't risk £2K of turbo's and possible engine damage if they come apart just for a noise LOL

As has been said, rally and F1 engines get replaced on a daily basis.